Friction Stir Welding Corrosion Resistance via Curable Coating
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Solution Overview
Problem
Friction stir welding processes face challenges in providing effective corrosion resistance at joints without using toxic, solvent-based wet sealants, which are time-consuming and messy, and can compromise joint quality over time.
Innovation Solution
A method involving a curable organic coating material with phenolic resin and organic solvent applied selectively to one article, allowing friction stir welding while maintaining the coating at the joint interface, which is then thermally treated to cure and provide corrosion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional wet sealants are used to seal the joint interface, then corrosion protection is provided, but the process becomes time-consuming and expensive
Solution Approach 1:
The patent combines the sealing function and corrosion protection function into a single curable coating material that is applied to the joint interface before welding. This eliminates the need for separate sealant application and curing steps, thereby reducing process time while maintaining effective corrosion protection.
Solution Approach 2:
The patent changes the chemical composition and curing mechanism of the coating material from conventional wet sealants to a curable organic coating that can be cured by the friction stir welding process itself. This parameter change allows the coating to transform from a liquid sealant to a cured protective layer during the welding process, eliminating additional sealing steps.
2Reliability
If conventional wet sealants are used for corrosion protection, then joint sealing is achieved, but the quality of joints is reduced due to squeezing, removal, or deterioration of sealants
Solution Approach 1:
The patent changes the physical and chemical parameters of the coating material to create a curable organic coating with controlled viscosity and curing characteristics. This coating maintains its position at the joint interface during welding without being squeezed out or removed, and does not deteriorate over time, thereby preserving joint quality while providing effective sealing.
Solution Approach 2:
The patent uses a coating material that is applied in a thin layer and cured in-situ during the welding process, eliminating the need for thick, long-lasting sealants that require precise positioning and maintenance. The coating serves its sealing function effectively during and after welding without compromising joint integrity.
3Reliability
If conventional wet sealants are used, then corrosion protection is provided, but toxic solvent-based compounds require extensive safety precautions and clean-up
Solution Approach 1:
The patent changes the chemical composition parameters of the coating material from toxic solvent-based compounds to a curable organic coating with non-toxic constituents. This coating provides equivalent or superior corrosion protection while eliminating the need for extensive safety precautions and caustic clean-up solutions.
Solution Approach 2:
The patent converts the potential harm of using liquid coatings during welding into a benefit by selecting a curable organic coating that not only withstands the welding process but also cures to provide enhanced corrosion protection. The coating transforms from a potential contaminant to a protective barrier during the welding process.
4Reliability
If curable organic coating material is applied selectively to the article, then corrosion resistance at the joint interface is enhanced, but the coating must be maintained during the friction stir welding process
Solution Approach 1:
The patent changes the thermal and chemical parameters of the coating material to ensure it remains stable during the friction stir welding process. The curable organic coating is formulated to withstand the temperatures and mechanical stresses of welding without degrading, while simultaneously providing corrosion resistance at the joint interface.
Solution Approach 2:
The patent applies the curable organic coating material to the joint interface before the friction stir welding process. This preliminary application ensures the coating is in position to provide corrosion protection, and the subsequent welding process cures the coating, locking it in place and enhancing its protective properties.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method enhances corrosion resistance at friction stir weld connections without the need for conventional wet sealants, ensuring joint integrity and safety by using a non-toxic, efficient, and durable organic coating that is cured simultaneously with the thermal treatment of the aluminum alloy components.
Implementation Method 1
The tool or pin generates sufficient friction within the structural articles to plasticize a portion of the articles
Implementation Method 2
The tool or pin generates sufficient friction within the structural articles to plasticize a portion of the articles, and the plasticized material is mixed by the pin
Implementation Method 3
The structural assembly is then heated to an elevated temperature sufficient to simultaneously heat-treat at least one of the articles and adequately cure the organic coating
Implementation Method 4
adequately cure the organic coating
Data Source
Figure 1
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AI summary
A method for forming a friction stir welded assembly is provided, as is an associated component assembly formed according to such a method. The method includes coating surface portions of one or more untreated articles with a coating material. Thereafter, the articles are friction stir welded to form an assembly. A thermal treatment is performed before or after the welding operation, e.g., to simultaneously heat treat the articles and cure the coating.